Diagnosis, Workup and Treatment
The patient underwent surgical unroofing of the iris cyst. Intraoperatively, three white foreign bodies were noted at the base and rim of the cyst, which were surgically excised and sent for pathologic evaluation. A black foreign body was removed from the iris surface above the pupil. Unfortunately, the specimens were too small to survive processing. The cilia was also removed.
Histopathologic inspection of the anterior cyst wall revealed non-keratinized squamous epithelium, consistent with the lining of an epithelial cyst and resembling corneal or limbal epithelium. A small segment of basement membrane was also visualized and could represent Descemet’s membrane.
Postoperatively, the patient was started on topical and a short course of oral steroids. The cyst has not recurred at one month follow-up.
Iris cysts comprise 21 percent of all iris tumors and can be categorized as iris pigment epithelial (IPE) cysts, stromal cysts or epithelial downgrowth cysts. IPE cysts are the most common iris tumor found in children, accounting for 28 percent of iris lesions. Iris cysts in children are more commonly found at the pupillary margin, when compared to the mid-zonal region, which is more common in adults. Pupillary IPE cysts are usually asymptomatic and remain stable without need for intervention.1 Rarely, they may be associated with vascular aneurysm due to mutation in the ACTA2 gene.
In a 1998 review of cystic iris lesions in children, it was found that only four of 57 iris cysts occurred from secondary causes. Of these four cases, two represented post-traumatic, epithelial ingrowth cysts, as was the case in our patient, while the other two arose from intraocular tumors. Both cases of post-traumatic, epithelial ingrowth cysts were managed with surgical excision. This is in contrast to the management of primary pupillary IPE cysts in children, which are generally observed.2
Stromal cysts, which are less common than IPE cysts, tend to enlarge progressively and can grow large enough to fill the anterior chamber and occlude the pupil. Due to their natural clinical course, stromal cysts usually require surgical intervention, which can include aspiration, excision, laser therapy or injection of absolute alcohol to induce sclerosis.3
Review of the literature reveals a case of a recurrent IPE cyst in a child after penetrating ocular trauma. On the third and final attempt at surgical excision, retained foreign body material from the initial injury was identified. As there was no subsequent recurrence after complete removal of the cyst with the foreign body, it was thought that the recurrence of the cyst was due to the retained material.4 Many cases of iris cysts after traumatic injuries are associated with retained cilia. A case of intraocular cilia and iris cyst remained asymptomatic for one year after injury until it presented as an intense uveitic reaction, which promptly resolved with removal of the cilia and iris cyst.5 Additionally, such iris cysts have been reported to occur as long as four years from the initial injury and inoculation of the cilia into the anterior chamber.6 Retained cilia are relatively inert and are rarely associated with infection. While cilia can be well-tolerated in the anterior chamber without adverse effects, the risk for iris cysts formation, uveitis and endophthalmitis is not negligible.6,7
We believe the cyst in our patient was due to retained foreign bodies, perhaps chicken and pepper, and the deposition of epithelial cells in the anterior chamber at the time of injury. When possible and safe to do so, primary repair of anterior chamber penetrating injuries should include consideration of possible foreign bodies by gonioscopy, ultrasound biomicroscopy and/or irrigation of the anterior chamber to ensure complete inspection and avoidance of retained foreign bodies.7 If a cyst develops postoperatively, missed retained foreign body should again be considered.
Once iris cysts due to foreign bodies occur, they are best managed with surgical excision with complete removal of the inciting foreign body. Attempts at YAG laser photocoagulation are often unsuccessful.6,8
The diagnosis of retained foreign body should always be kept in mind for patients who have had penetrating trauma, even years after injury. REVIEW
1. Shields CL, Kancherla S, Patel J, et al. Clinical survey of 3680 iris tumors based on patient age at presentation. Ophthalmology 2012;119:407-414.
2. Shields JA, Shields CL, Lois N, et al. Iris cysts in children: Classification, incidence and management. The 1998 Torrence A Makley Jr. Lecture. Br J Ophthalmol 1999,83:334-8.
3. Shields CL, Arepalli S, Lally SE, et al. Iris stromal cyst management with alcohol-induced sclerosis in 16 patients. JAMA Ophthalmol 2014;132:703-8.
4. Bhattacharjee H, Das D. Recurrent iris cyst following pencil tip injury. Indian J Med Res 2013:137:1211.
5. Kose S, Kavikcioglu O, Akkin C, et al. Coexistence of intraocular eyelashes and anterior chamber cyst after penetrating eye injury: A case presentation. Int Ophthalmol 1994-1995;18:309-311.
6. Hoh HB, Menage MJ, Dean-Hart C. Iris cyst after traumatic implantation of an eyelash into the anterior chamber. Br J Opthalmol 1993;77:741-2.
7. Soloman A, Chowers I, Frucht-Perry J. Retained eyelashes in the anterior chamber following corneal perforation. Eye 1998;12:1031-2.
8.Zhai H, Liu T, Xie L, et al. An unusual case of epidermal iris cyst. Ophthalmology 2013;120:1305-6.